Volumetric Clouds not working with orthographic camera.

Hi guys,

I have a top down camera that is set to orthographic and some basic volumetric height fog set up with a box that has a volumetric material applied to it. It all works, I see it in editor and when playing a camera that is set to perspective I can also see the volumetric clouds.
However, when switching to orthographic view, the clouds are simply not being rendered.
I tried various settings or thought it was some clipping issue but after going through all settings I am out of ideas.

Maybe its just a setting I am overlooking or is it a rendering bug? If this is intentional, does somebody know why volumetrics do not render with orthographic cameras?

Thanks in advance!